NRG Energy announced on Thursday it was acquiring Goal Zero, a company that makes portable solar battery chargers. Goal Zero's products include small, hand-held solar chargers that can be used to power cell phones, mp3 players and other lower-power device, all the way up to large chargers that can keep a refrigerator and other big home appliances going.

"The ultimate manifestation of distributed clean generation is personal power,” David Crane, NRG's president and CEO, said in a press statement. “Only about one in four Americans are themselves homeowners but every American has a need for personal energy free from the tether of plug and cord."

The Goal Zero devices were reportedly created with an eye toward humanitarian issues, such as bringing readily-usable power sources into developing countries or assisting during a major disaster somewhere that destroys the local power grid. But the Goal Zero products have also gotten consumer traction from campers and folks in the adventure sports community.

According to NRG, the Goal Zero acquisitive helps the “third leg” of NRG's consumer strategy: to bring together opportunities with system power, residential solar and personal power offerings.

Some other, old-school energy companies are taking a new look at solar power. Here are some examples:

While not exactly mobile, Chevron has worked with BrightSource Energy for the past several years on the world's largest solar-enhanced oil recovery project at Chevron's oil field in Coalinga, California. The solar facilitity generates steam, which is injected underground to make the field's heavy crude oil easier to produce.

The solar-to-steam project is being used to test the commercial viability of solar power at such oil fields in lieu of gas-fired steam generators.

One of the largest natural gas producers in the United States, Pittsburgh-based EQT uses solar power to run its remote well-site equipment.

“It’s rare that we run electricity to a site, unless there is certain equipment that requires a much larger draw, like a pumping unit,” Linda Robertson, an EQT spokeswoman, told the Pittsburgh Post-Gazette last month. “We use solar to power electronics that have been installed on each well once our wells are turned into production."